Non-crystallizing bis-oxazolidines

ABSTRACT

Non-crystallizing oxazolidines as curing agents for polyisocyanates and polyurethanes. The curing agents are mixtures of at least one polyoxazolidine POU having at least two urethane groups and at least one polyoxazolidine POC having at least one carbonato group.

RELATED APPLICATIONS

This application claims priority as a continuation application under 35U.S.C. §120 to PCT/EP2010/065998, which was filed as an InternationalApplication on Oct. 22, 2010 designating the U.S., and which claimspriority to European Application No. 09174683.4 filed in Europe on Oct.30, 2009. The entire contents of these applications are herebyincorporated by reference in their entireties.

FIELD

This disclosure relates to the field of oxazolidine curing agents forpolyisocyanates and polyurethanes.

BACKGROUND INFORMATION

Oxazolidines, particularly bis-oxazolidines, are well known as curingagents for polyurethanes. Particularly useful as curing agents arebis-oxazolidines which are linked by urethane groups, disclosed, forexample, in U.S. Pat. No. 5,747,627, U.S. Pat. No. 5,189,176 and GBPatent Document No. 1 463 944.

A further class of oxazolidines are bis-oxazolidines which are linked bycarbonato groups. Such bis-oxazolidines are disclosed, for example, inEP Patent Document No. 0 499 188 A1.

A further class of oxazolidines are bicyclic oxazolidines which aredisclosed, for example, in U.S. Pat. No. 5,126,421, InternationalPublication No. WO 96/08308 A1, International Publication No. WO99/07762 A1 and GB Patent Document No. 1 292 455.

Polyoxazolidines in general, and particularly polyoxazolidines havingurethane groups, however, tend to crystallize. This is verydisadvantageous in view of storage, transport and application of thesecompounds. There have been several approaches to solve this problem. Theuse of solvents show disadvantages such as impairment of mechanicalproperties and release of solvents such as volatile organic compounds(VOC).

U.S. Pat. No. 5,189,176 suggests a non-crystallising bisoxazolidinehaving two urethane groups linked together by a hexamethylene group andhaving a hydrocarbon substituent with 5 to 8 carbon atoms attached tothe carbon located between the oxygen and nitrogen atom of theoxazolidine ring. However, this very narrow group of chemical compoundsis very restrictive in the choice of suitable properties ofpolyoxazolidines.

SUMMARY

According to an exemplary aspect, a composition is disclosed,comprising: a) at least one polyoxazolidine POU having at least twourethane groups; and b) at least one polyoxazolidine POC having at leastone carbonato group.

According to another exemplary aspect, a method of using a compositionas a non-crystallizing curing agent of a polyisocyanate is disclosed,the method comprising adding a composition to a polyisocyanate, whereinthe composition comprises: a) at least one polyoxazolidine POU having atleast two urethane groups; and b) at least one polyoxazolidine POChaving at least one carbonato group.

Disclosed are non-crystallising polyoxazolidines that provide a broadchoice of properties of polyoxazolidines.

In an exemplary embodiment, these polyoxazolidines are not based onsolvents and, therefore, can be ecologically and economicallyadvantageous. An exemplary advantage is that a broad range of existingcrystallizing polyoxazolidines can be modified to yieldnon-crystallizing polyoxazolidine compositions. This allows for thepossibility to tailor the curing properties to the customers' needs.

DETAILED DESCRIPTION

Disclosed in a first aspect is a composition comprising:

-   -   a) at least one polyoxazolidine POU having at least two urethane        groups and    -   b) at least one polyoxazolidine POC having at least one        carbonato group.

All bold indications in this document such as POU, POC, BCO or the likeare used only for informative purposes and serve only to aidunderstanding and identification.

The term “urethane groups” shall mean in the present document a group ofthe formula (a):

Dotted lines indicate in the present document the binding site to othersubstituents.

The term “carbonato group” shall mean in the present document a group ofthe formula (b):

The term “room temperature” shall mean in the present document atemperature of 25° C.

The term “bicyclic polyoxazolidine” shall mean in the present document acompound having two oxazolidines ring which are fused together, in otherwords a compound comprising the structural element of the formula (c)

The term “consists essentially of” shall mean in the present documentthat, apart from the mentioned components, only minor amounts, forexample, less than 5% by weight, for example, less than 1% by weight, ofother ingredients are present.

The term “polyurethane” shall mean any product of the addition reactionof polyisocyanate and polyols and/or polymercaptans and eventuallywater, independently whether some isocyanate groups remain or not. Forexample, the so-called polyurethane prepolymers, which are curable byhumidity due to the isocyanate groups, are also regarded aspolyurethanes as well as, for example, the completely cured polymerhaving essentially no NCO groups left.

The exemplary composition comprises at least one polyoxazolidine POUhaving at least two urethane groups.

For example, the polyoxazolidine POU having at least two urethane groupshas a structure according to formula (I), for example, formula (Ia):

wherein

-   -   R¹ is an alkylene group with 2 to 5 carbon atoms, for example,        an ethylene group;    -   R² and R³ are, individually, H or a linear or branched alkyl        group with 1 to 10 carbon atoms or an aryl group which is        optionally substituted;    -   R⁴ is a n-valent residue of a polyisocyanate of the molecular        weight of 150-4000 g/mol, for example, of 160-1000 g/mol, after        removal of n isocyanate groups; and    -   n=2, 3, 4, 5 or 6.

For example, n stands for a value of 2, i.e., the polyoxazolidine POUcan be bis-oxazolidine.

The substituent R⁴ can be selected from, for example:

or the isocyanurates or biurets or uretdiones of the correspondingdiisocyanates thereof.

Those substituents R⁴ originating from isocyanurates or biurets oruretdiones of the corresponding diisocyanates can have one of thefollowing structural formulas:

In these formulas, R^(a) stands for the corresponding diisocyanate afterremoval of the two NCO groups.

For example, the substituent R⁴ can be selected from 1,6-hexamethylenediisocyanate (HDI),1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (isophoronediisocyanate or IPDI), 2,4-toluene diisocyanate, 2,6-toluenediisocyanate and the isocyanurates or biurets or uretdiones thereofafter removal of n NCO groups.

The polyoxazolidine POU having at least two urethane groups can beprepared by a reaction of a polyisocyanate, for example, apolyisocyanate of formula (IA), and an oxazolidine having a substituentcarrying a hydroxyl group, for example, an oxazolidine of formula (IB),for example, of formula (IB-1).

The oxazolidine having a substituent carrying a hydroxylic group can bemade from a condensation reaction of an N-hydroalkylethanolamine, forexample, of a diethanolamine, and the corresponding ketone R²COR³,respectively and for example, the corresponding aldehyde HCOR³.

Suitable polyisocyanates of formula (IA) can be selected from1,6-hexamethylene diisocyanate (HDI), 2-methylpentamethylene1,5-diisocyanate, 2,2,4- and 2,4,4-trimethyl-1,6-hexamethylenediisocyanate (TMDI), 1,10-decamethylene diisocyanate,1,12-dodecamethylene diisocyanate, lysine diisocyanate and lysine esterdiisocyanate, cyclohexane 1,3- and 1,4-diisocyanate and any desiredmixtures of these isomers, 1-methyl-2,4- and-2,6-diisocyanatocyclohexane and any desired mixtures of these isomers(HTDI or H₆TDI),1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (=isophoronediisocyanate or IPDI), perhydro-2,4′- and -4,4′-diphenylmethanediisocyanate (HMDI or H₁₂MDI),1,4-di-isocyanato-2,2,6-trimethylcyclohexane (TMCDI), 1,3- and1,4-bis(isocyanato-methyl)cyclohexane, m- and p-xylylene diisocyanate(m- and p-XDI), m- and p-tetramethyl-1,3- and -1,4-xylylene diisocyanate(m- and p-TMXDI), bis(1-isocyanato-1-methylethyl)naphthalene, 2,4- and2,6-toluene diisocyanate (TDI), 4,4′-, 2,4′- and 2,2′-diphenylmethanediisocyanate (MDI), 1,3- and 1,4-phenylene diisocyanate,2,3,5,6-tetramethyl-1,4-diisocyanatobenzene, naphthalene1,5-diisocyanate (NDI), 3,3′-dimethyl-4,4′-diisocyanatodiphenyl (TODD,dianisidine diisocyanate (DADI), oligomers and polymers of theaforementioned isocyanates, and any desired mixtures of theaforementioned isocyanates. In an exemplary embodiment, thepolyisocyanate can include monomeric diisocyanates such as MDI, TDI,HDI, H₁₂MDI and IPDI.

The polyisocyanate of formula (IA) can be selected from, for example,the isocyanurates or biurets or uretdiones of the aforementionedpolyisocyanates.

The polyisocyanate of formula (IA) can be selected from, for example,the isocyanate groups carrying polyurethane prepolymers being a reactionproduct of aforementioned polyisocyanates with polyols and/orpolyamines.

The polyisocyanate of formula (IA) can be selected from, for example,1,6-hexamethylene diisocyanate (HDI),1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (isophoronediisocyanate or IPDI), 2,4-toluene diisocyanate, 2,6-toluenediisocyanate.

The polyisocyanates can be selected from, for example, diisocyanatessuch as, for example, HDI and TDI.

Examples include polyoxazolidines PUC which are bis-oxazolidines offormula (IV) or (IV′):

R² and R³ being already defined above. In an exemplary embodiment, R²represents H.

The above described polyoxazolidines POU having at least two urethanegroups can be liquids at room temperature, which tend to otherwisecrystallize on storage at low temperature. For example, thecrystallization can occur within less than 1 week's time at atemperature of 4° C. Crystallization seeds can accelerate thiscrystallization process.

The exemplary composition comprises at least one polyoxazolidine POChaving at least one carbonato group.

For example, the polyoxazolidine POC having at least one carbonato grouphas a structure according to formula (II), for example, formula (IIa):

-   -   wherein    -   R⁵ is an alkylene group with 2 to 5 carbon atoms, for example,        an ethylene group;    -   R⁶ and R⁷ are, individually, H or a linear or branched alkyl        group with 1 to 6 carbon atoms or an aryl group which is        optionally substituted;    -   m=1, 2, 3, 4, 5 or 6;    -   R⁸ is a m-valent residue of the molecular weight of 15-1000        g/mol, for example, carrying a substituent of the formula (III)

For example, n stands for a value of 2, for example, the polyoxazolidinePOC can be a bis-oxazolidine.

The polyoxazolidine POC can be prepared by a reaction of an organiccarbonate, eventually a polyol, for example, a polyol of formula (II A),an oxazolidine having a substituent carrying a hydroxyl group, forexample, an oxazolidine of formula (II B), for example, of formula (IIB-1):

The details of this reaction and the products thereof formed aredescribed in EP Patent Document No. 0 499 188 A1, the entire disclosureof which is hereby incorporated by reference.

Suitable polyols of formula (IA) can be selected from, for example,1,2-ethanediol, diethylene glycol, 1,2-propanediol, dipropylene glycol,1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol,octanediol, nonanediol, decanediol, neopentyl glycol, pentaerythritol(=2,2-bis(hydroxymethyl)-1,3-propanediol), dipentaerythritol(=3-(3-hydroxy-2,2-bishydroxymethylpropoxy)-2,2-bishydroxymethylpropan-1-01),glycerol (=1,2,3-propanetriol), trimethylolpropane(=2-ethyl-2-(hydroxymethyl)-1,3-propanediol), trimethylolethane(=2-(hydroxymethyl)-2-methyl-1,3-propanediol), di(trimethylolpropane)(=3-(2,2-bis(hydroxymethyl)butoxy)-2-ethyl-2-hydroxymethylpropan-1-ol),di(trimethylolethane)(=3-(3-hydroxy-2-hydroxymethyl-2-methylpropoxy)-2-hydroxymethyl-2-methylpropan-1-ol),diglycerol (=bis(2,3-dihydroxypropyl)ether;cyclohexane-1,2-diyldimethanol, cyclohexane-1,3-diyldimethanol,cyclohexane-1,4-diyldimethanol, 1,2-cyclohexanediol,1,3-cyclohexanediol, 1,4-cyclohexanediol,1,3,5-tris(2-hydroxyethyl)-1,3,5-triazinane-2,4,6-trione,2,2′,2″-nitrilotriethanol; (poly)ethylene glycols, (poly)propyleneglycols and (poly)butylene glycol(=poly(oxy-1,4-butanediyl)-α-hydro-ω-hydroxyl).

The oxazolidine having a substituent carrying a hydroxyl group can bemade from a condensation reaction of an N-hydroxyalkylethanolamine, forexample, a diethanolamine, and the corresponding ketone R⁶COR⁷respectively and, for example, the corresponding aldehyde HCOR⁷.

Exemplary polyoxazolidines POC are those which are selected from:

-   -   wherein R⁶ and R⁷ are, individually, H or a linear or branched        alkyl group with 1 to 10 carbon atoms or an aryl group which is        optionally substituted, for example, a methyl, ethyl or        isopropyl group.

An exemplary composition comprises:

-   -   a) at least one polyoxazolidine POU having at least two urethane        groups and    -   b) at least one polyoxazolidine POC having at least one        carbonato group.

The composition can comprise or consists of a polyoxazolidine PUC whichis a bis-oxazolidine of formula (IV) or (IV′) and a polyoxazolidine POCwhich is a bis-oxazolidine of formula (V)

-   -   wherein R², R³, R⁶ and R⁷ represent independently from each        other H or a linear or branched alkyl group with 1 to 10 carbon        atoms, for example, a methyl, ethyl or isopropyl group, for        example, an isopropyl group.

In an exemplary embodiment, R² and R⁶ are H.

In an exemplary embodiment, the composition further comprises at leastone bicyclic oxazolidine BCO. Exemplary bicyclic oxazolidine BCO includethose having a structure according to formula (VI)

-   -   wherein R⁹, R¹⁰, R¹¹ and R¹² are, individually, a linear or        branched alkyl group, for example, with 1 to 8 carbon atoms, or        a linear or branched hydroxy alkyl group, for example, with 1 to        8 carbon atoms, or an aryl group or a cycloalkyl group, for        example, with 6 to 12 carbon atoms;    -   R¹³ is H or a linear or branched alkyl group, for example, with        1 to 8 carbon atoms, or a linear or branched hydroxy alkyl        group, for example, with 1 to 8 carbon atoms;    -   R¹⁴, R¹⁵, R¹⁶ and R¹⁷ are, individually, H or a linear or        branched alkyl group, for example, with 1 to 8 carbon atoms, or        a linear or branched hydroxy alkyl group, for example, with 1 to        8 carbon atoms.

In an exemplary embodiment, R⁹ and R¹¹ are H.

The bicyclic oxazolidine BCO can be prepared in any suitable mannerincluding, for example, in accordance with the method of preparing anddetails of the products formed in U.S. Pat. No. 5,126,421 andInternational Publication No. WO 96/08308 A1, the entire disclosures ofwhich is hereby incorporated by reference.

An exemplary bicyclic oxazolidine BCO includes the compound1-aza-3,7-dioxo-2,8-diisopropyl-5-ethyl bicyclo[3,3,0]octane, availableunder the tradename ZOLDINE® RD-20 from Angus Chemical Company (BuffaloGrove, USA) and has a structure of formula (VI) in which R⁹, R¹¹, R¹⁴,R¹⁵, R¹⁶ and R¹⁷ are all H; R¹⁰ and R¹² are an isopropyl group and R¹³is an ethyl group.

For example, the amount of all polyoxazolidines POC and all of theoptionally present bicyclic oxazolidines BCO and the sum of allpolyoxazolidines POU is 80-100% by weight, for example, 90-100% byweight, for example, 95-100% by weight, with regard to the weight of thetotal composition.

The weight ratio of the sum of all polyoxazolidines POC to the sum ofall polyoxazolidines POU can be, for example, 5:95-95:5, for example,10:90-45:55, for example, 25:75-35:65.

In an exemplary embodiment, the composition is used as a curing agentwhich is suitable for adding to polyisocyanates or polyurethanes. Inthis embodiment, the composition can consist essentially of, forexample, consist only of, polyoxazolidine(s) POC, polyoxazolidine(s) POUand optionally bicyclic oxazolidines(s) BCO. For example, thecomposition does not have any solvents, as ingredients. Such curingagent compositions can be liquid at room temperature and have incomparison with the polyoxazolidine(s) POU a distinctly reduced tendencyto crystallize. These compositions can have remarkably better storageand transport properties and can need less expensive storage equipmentor application equipment and are, therefore, very advantageous.

Said compositions can be advantageous over existing polyoxazolidines inthat, for example, a broad range of non-crystallizing curing agents cannow be offered, allowing tailoring the curing properties to thecustomers' needs, for example, by also using polyoxazolidine(s) POUwhich are otherwise prone to crystallization when used as such.

A further exemplary aspect relates to the use of the composition asdescribed before as a non-crystallizing curing agent forpolyisocyanates.

In a further exemplary embodiment, the composition as described beforefurther comprises a polyisocyanate, for example, a polymer having atleast two NCO groups. In other words, this embodiment of the compositioncorresponds to the composition according to the first embodiment, whichhas been added to a polyisocyanate or polyurethane composition.

In this embodiment, the amount of all polyoxazolidines POC and bicyclicoxazolidines BCO and the sum of all polyoxazolidines POU can be 5-20% byweight, for example, 5-15% by weight, for example, 6-10% by weight, inregard to the weight of the total composition.

As additional polyisocyanates for this embodiment, those polyisocyanatescan be used that have been described above for the manufacture ofpolyoxazolidine POU having at least two urethane groups.

Furthermore, polyurethane prepolymers carrying isocyanate groups can beused as additional polyisocyanates. These polyurethane prepolymers canbe prepared from the above mentioned polyisocyanates and polyols.

Polyols suited for the preparation of polyurethane prepolymers can beselected from, for example:

-   -   polyetherpolyols, also known as polyoxyalkylenepolyols or        oligoetherols, which are polymerization products of ethylene        oxide, 1,2-propylene oxide, 1,2- or 2,3-butylene oxide, oxetane,        tetrahydrofuran or mixtures thereof, possibly polymerized with        the aid of a initiator molecule with two or more active hydrogen        atoms, for example water, ammonia or compounds having a        plurality of OH or NH groups, for example 1,2-ethanediol, 1,2-        and 1,3-propanediol, neopentyl glycol, diethylene glycol,        triethylene glycol, the isomeric dipropylene glycols and        tripropylene glycols, the isomeric butanediols, pentanediols,        hexanediols, heptanediols, octanediols, nonanediols,        decanediols, undecanediols, 1,3- and 1,4-cyclohexanedimethanol,        bisphenol A, hydrogenated bisphenol A, 1,1,1-trimethylolethane,        1,1,1-trimethylolpropane, glycerol, aniline, and mixtures of the        compounds mentioned. It is possible to use either        polyoxyalkylenepolyols which have a low degree of unsaturation        (measured to ASTM D-2849-69 and reported in milliequivalents of        unsaturation per gram of polyol (meq/g)), prepared, for example,        with the aid of double metal cyanide complex catalysts (DMC        catalysts), or polyoxyalkylenepolyols with a higher degree of        unsaturation, prepared, for example, with the aid of anionic        catalysts such as NaOH, KOH, CsOH or alkali metal alkoxides.

Suitable are polyoxyethylenepolyols and polyoxypropylenepolyols, forexample, polyoxyethylenediols, polyoxypropylenediols,polyoxyethylenetriols and polyoxypropylenetriols.

Suitable are polyoxyalkylenediols or polyoxyalkylenetriols having adegree of unsaturation lower than 0.02 meq/g and having a molecularweight in the range from 1000 to 30 000 g/mol, and alsopolyoxyethylenediols, polyoxyethylenetriols, polyoxypropylenediols andpolyoxypropylenetriols with a molecular weight of 400 to 8000 g/mol.“Molecular weight” or “molar mass” is understood in the present documentalways to mean the molecular weight average M_(n).

Suitable are so-called ethylene oxide-terminated (“EO-endcapped”,ethylene oxide-endcapped) polyoxypropylenepolyols. The latter arespecific polyoxypropylenepolyoxyethylenepolyols which are obtained, forexample, by further alkoxylating pure polyoxypropylenepolyols, forexample, polyoxypro-pylenediols and -triols, with ethylene oxide oncompletion of the polypropoxylation reaction, and have primary hydroxylgroups as a result. Preference can be given in this case topolyoxypropylenepolyoxyethylenediols andpolyoxypropylenepolyoxyethylenetriols.

-   -   Styrene-acrylonitrile- or acrylonitrile-methyl        methacrylate-grafted polyether-polyols.    -   PolCterpolyols, also known as oligoesterols, prepared, for        example, from di- to trihydric alcohols, for example        1,2-ethanediol, diethylene glycol, 1,2-propanediol, dipropylene        glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol,        neopentyl glycol, glycerol, 1,1,1-trimethylolpropane or mixtures        of the aforementioned alcohols, with organic dicarboxylic acids        or the anhydrides or esters thereof, for example succinic acid,        glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic        acid, dodecanedicarboxylic acid, maleic acid, fumaric acid,        phthalic acid, isophthalic acid, terephthalic acid and        hexahydro-phthalic acid, or mixtures of the aforementioned        acids, and also polCterpolyols formed from lactones, for example        from c-caprolactone.    -   Polycarbonatepolyols, as obtainable by reaction, for example, of        the abovementioned alcohols—used to form the        polyesterpolyols—with dialkyl carbonates, diaryl carbonates or        phosgene.    -   Polyacrylate- and polymethacrylatepolyols.    -   Poly-hydroxy-functional fats and oils, for example natural fats        and oils, for example, castor oil; or polyols—known as        oleochemical polyols—obtained by chemical modification of        natural fats and oils, for example the epoxy polCters or epoxy        polyethers obtained by epoxidation of unsaturated oils and        subsequent ring opening with carboxylic acids or alcohols, or        polyols obtained by hydroformylation and hydrogenation of        unsaturated oils; or polyols obtained from natural fats and oils        by degradation processes such as alcoholysis or ozonolysis and        subsequent chemical linkage, for example by transesterification        or dimerization, of the degradation products or derivatives        thereof thus obtained. Suitable degradation products of natural        fats and oils are, for example, fatty acids and fatty alcohols,        and also fatty acid esters, for example, the methyl esters        (FAME), which can be derivatized, for example, by        hydroformylation and hydrogenation to hydroxy fatty acid esters.    -   Polyhydrocarbonpolyols, also known as oligohydrocarbonols, for        example poly-hydroxy-functional ethylene-propylene,        ethylene-butylene or ethylene-propylene-diene copolymers, as        produced, for example, by Kraton Polymers, or        poly-hydroxy-functional copolymers of dienes such as        1,3-butadiene or diene mixtures, and vinyl monomers such as        styrene, acrylonitrile or isobutylene, or        poly-hydroxy-functional polybutadienepolyols, for example those        which are prepared by copolymerization of 1,3-butadiene and        allyl alcohol and may also be hydrogenated.    -   Poly-hydroxy-functional acrylonitrile/butadiene copolymers, as        can be prepared, for example, from epoxides or amino alcohols        and carboxyl-terminated acrylonitrile/butadiene copolymers        (commercially available under the Hypro® CTBN (formerly Hycar®        CTBN) name from Noveon).

These polyols mentioned can have a mean molecular weight of 250-30 000g/mol, for example, 1000-30 000 g/mol, and can have a mean OHfunctionality in the range from 1.6 to 3.

Suitable polyols are polCterpolyols and polyetherpolyols, for example,polyoxyethylenepolyol, polyoxypropylenepolyol andpolyoxypropylenepolyoxy-ethylenepolyol, for example,polyoxyethylenediol, polyoxypropylenediol, polyoxy-ethylenetriol,polyoxypropylenetriol, polyoxypropylenepolyoxyethylenediol andpolyoxypropylenepolyoxyethylenetriol.

In addition to these polyols mentioned, small amounts of low molecularweight di- or polyhydric alcohols, for example, 1,2-ethanediol, 1,2- and1,3-propanediol, neopentyl glycol, diethylene glycol, triethyleneglycol, the isomeric dipropylene glycols and tripropylene glycols, theisomeric butanediols, pentanediols, hexanediols, heptanediols,octanediols, nonanediols, decanediols, undecanediols, 1,3- and1,4-cyclohexanedimethanol, hydrogenated bisphenol A, dimeric fattyalcohols, 1,1,1-trimethylolethane, 1,1,1-trimethylolpropane, glycerol,pentaerythritol, sugar alcohols such as xylitol, sorbitol or mannitol,sugars such as sucrose, other higher polyhydric alcohols, low molecularweight alkoxylation products of the aforementioned di- and polyhydricalcohols, and mixtures of the aforementioned alcohols, can be usedadditionally in the preparation of the polyurethane prepolymer.

These compositions may further comprise other ingredients such asfiller, adhesion promoters, stabilizers, thixotropic agents, curingcatalysts and other additives which are known to the person skilled inthe art of polyurethane compositions.

The filler can influence both the rheological properties of the uncuredcomposition, and the mechanical properties and the surface properties ofthe cured composition. Suitable fillers are inorganic and organicfillers, for example natural, ground or precipitated calcium carbonateswhich are optionally coated with fatty acids, for example, stearates,barium sulfate (BaSO₄, also known as barite or heavy spar), calcinedkaolins, quartz flour, aluminum oxides, aluminum hydroxides, silicas,for example, high-dispersity silicas from pyrolysis processes, carbonblacks, for example, industrially produced carbon black, PVC powders orhollow spheres. Exemplary fillers are barium sulfate and calciumcarbonates, carbon black and flame-retardant fillers such as hydroxidesor hydrates, for example, hydroxides or hydrates of aluminum, forexample, aluminum hydroxide.

These compositions can cure very rapidly and can have advantages, forexample, in that the curing behaviour can be easily varied by the choiceof the structures of polyoxazolidine(s) PUC and polyoxazolidine(s) POC.

The compositions can be used in a broad scope of applications, forexample, as coatings, adhesives, sealants, as compositions for flooringor for molding.

These compositions can be suited to be used in the field of repair,civil engineering and industrial manufacturing of goods, for example, inthe manufacturing of vehicles such as cars.

EXAMPLES

The following examples serve to illustrate the aspects described above.

Synthesis of 2-(2-isopropyloxazolidin-3-yl)ethanol (i-Pr-OE)

1495.07 g (14.2 moles) diethanolamine and 400 g of light petroleumnaphtha solvent were added to a 5 litre reaction flask equipped with astirrer and reflux condenser. The mixture was heated to 40° C. using aheating mantle and 1104.9 g (15.3 moles) of isobutyraldehyde slowlyadded over a period of 1 hour, whilst maintaining the reactiontemperature below 60° C. Once all of the isobutyraldehyde had beenadded, Dean and Stark apparatus was added to the reaction vessel and themixture heated to 85° C. The reaction was maintained between 80-85° C.until 254.3 g of water had distilled off. The reaction temperature wasthen raised to 125° C. and the solvent and excess isobutyraldehydedistilled off under reduced pressure (approx. 0.8 bar).

The resultant 2-(2-isopropyloxazolidin-3-yl)ethanol (i-Pr-OE) wasisolated as a yellow oil with a purity of 97.1% (determined by GC).

Synthesis of Polyoxazolindine POU-1

994.6 g (6.3 moles) of 2-(2-isopropyloxazolidin-3-yl)ethanol (i-Pr-OE)and 0.12 g DBTDL catalyst were added to a 1 litre reaction vessel. 335.5g (1.9 moles) of toluene diisocyanate (Desmophen T80) (a 80:20 mixtureof 2,4- and 2,6-toluene diisocyanate) was added dropwise over a 2 hourperiod. The reaction mixture was held at 90-100° C. for 1.5-2 hoursusing gentle heating. End of reaction was determined by IR analysis andthe disappearance of the NCO peak at 2275 cm⁻¹. The finalbis-oxazolidine product POU-1 was isolated as a viscous pale yellowliquid with a viscosity of 21.4 Pa·s (214 P) determined by Brookfield at20° C.

Synthesis of Polyoxazolindine POC-1

1081.98 g (6.8 moles) of 2-(2-isopropyloxazolidin-3-yl)ethanol(i-Pr-OE), 912.9 g (10.1 moles) dimethyl carbonate and 5.12 g ofpotassium tert-butoxide were added to a 2 litre reaction flask equippedwith a reflux condenser and heated to 80° C. The transesterification wascarried out for 6 hours at 80-100° C. under nitrogen after which thebatch was set-up for reflux and the methanol removed between 80-130° C.112.3 g methanol was collected. Excess mass collected was attributed toexcess dimethyl carbonate. The final bis-oxazolidine POC-1 was isolatedas a free flowing yellow liquid with a viscosity of 48.2 mPa·s (48.2 cP)(method used see above: synthesis of POU-1) with a purity of 77%(determined by GC).

Synthesis of Polyoxazolidine POU-2

668.8 g (4.2 moles) of 2-(2-isopropyloxazolidin-3-yl)ethanol (i-Pr-OE)and 0.08 g DBTDL catalyst were added to a 1 litre reaction vessel. 331.1g (2.0 moles) of hexamethylene 1,6-diisocyanate (HDI) was added dropwiseover a 1.5 hour period whilst maintaining the reaction temperature below100° C. The reaction mixture was then held at 90-100° C. for 2 hoursusing gentle heating. End of reaction was determined by IR analysis andthe disappearance of the NCO peak at 2275 cm⁻¹. The finalbis-oxazolidine product POU-2 was isolated as a viscous yellow liquidwith a viscosity of 15.4 Pa·s (154 P) (method used see above: synthesisof POU-1).

Storage Stability Tests

The polyoxazolidines respectively the mixtures (being prepared by mixingthe two polyoxazolidines in the mixing ratio indicated in table 1 in amixing vessel under nitrogen during 30 minutes at 60° C.) were tested inview of their storage stability, respectively on their tendency tocrystallize.

For this the examples of comparison (Ref. 1, Ref. 2 and Ref. 3) as wellas the examples (1, 2, 3 and 4) are individually stored in sealedcontainers at 4° C. and at −12.5° C. The samples were checked regularlyto determine whether or not they have crystallized. In table 1 it wasindicated if the sample has been crystallized (“C”) or not crystallized(“NC”) or partly crystallized (“PC”)

In a further series of experiment a few crystals of POU-2 were addedinitially as crystallization seeds to each of the different samples andthe crystallization behaviour was checked analogously.

TABLE 1 compositions and storage stability Ref. 1 Ref. 2 1 2 3 4 5 POU-1[% by weight] 100 90 80 75 65 POU-2 [% by weight] 100 80 POC-1 [% byweight] 10 20 25 35 20 Storage Stability non-seeded 1 day at 4° C. C CNC NC NC NC NC 1 week at 4° C. C C NC NC NC NC NC 2 weeks at 4° C. C CNC NC NC NC NC 1 month at 4° C. C C NC NC NC NC PC 6 months at 4° C. C CNC NC NC NC C 12 months at 4° C. C C NC NC NC NC C 1 day at −12.5° C. CC NC NC NC NC NC 1 week at −12.5° C. C C NC NC NC NC PC 2 weeks −12.5°C. C C NC NC NC NC C 1 month −12.5° C. C C NC NC NC NC C 6 months −12.5°C. C C NC NC NC NC C 12 months −12.5° C. C C NC NC NC NC C seeded 1 dayat 4° C., seeded C C NC NC NC NC NC 1 week at 4° C., seeded C C NC NC NCNC PC 2 weeks at 4° C., seeded C C NC NC NC NC C 1 month at 4° C.,seeded C C NC NC NC NC C 6 months at 4° C., seeded C C NC NC NC NC C 12months at 4° C., seeded C C NC NC NC NC C 1 day at −12.5° C., seeded C CNC NC NC NC NC 1 week at −12.5° C., seeded C C NC NC NC NC C 2 weeks−12.5° C., seeded C C NC NC NC NC C 1 month −12.5° C., seeded C C NC NCNC NC C 6 months −12.5° C., seeded C C NC NC NC NC C 12 months −12.5°C., seeded C C NC NC NC NC C

The results of table 1 show that the examples 1, 2 and 3 have a muchbetter storage stability as compared to the polyoxazolidines having atleast two urethane groups alone (Ref. 1 and Ref. 2).

It will be appreciated by those skilled in the art that the presentinvention can be embodied in other specific forms without departing fromthe spirit or essential characteristics thereof. The presently disclosedembodiments are therefore considered in all respects to be illustrativeand not restricted. The scope of the invention is indicated by theappended claims rather than the foregoing description and all changesthat come within the meaning and range and equivalence thereof areintended to be embraced therein.

1. A composition, comprising: a) at least one polyoxazolidine POU havingat least two urethane groups; and b) at least one polyoxazolidine POChaving at least one carbonato group.
 2. The composition according toclaim 1, wherein the polyoxazolidine POU has a structure according toformula (I):

wherein R¹ is an alkylene group with 2 to 5 carbon atoms; R² and R³ are,individually, H or a linear or branched alkyl group with 1 to 10 carbonatoms or an aryl group which is optionally substituted; R⁴ is a n-valentresidue of a polyisocyanate of the molecular weight of 150-4000 g/mol,after removal of n isocyanate groups; and n=2, 3, 4, 5 or
 6. 3. Thecomposition according to claim 2, wherein R⁴ is selected from the groupconsisting of:

or the isocyanurates or biurets or uretdiones of the correspondingdiisocyanates thereof.
 4. The composition according to claim 2, whereinR⁴ is selected from the group consisting of 1,6-hexamethylenediisocyanate (HDI),1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (isophoronediisocyanate or IPDI), 2,4-toluene diisocyanate, 2,6-toluenediisocyanate and the isocyanurates or biurets or uretdiones thereofafter removal of n NCO groups.
 5. The composition according to claim 1,wherein the polyoxazolidine POC has a structure according to formula(II):

wherein R⁵ is an alkylene group with 2 to 5 carbon atoms; R⁶ and R⁷ are,individually, H or a linear or branched alkyl group with 1 to 6 carbonatoms or an aryl group which is optionally substituted; m=1, 2, 3, 4, 5or 6; R⁸ is a m-valent residue of a molecular weight of 15-1000 g/mol.6. The composition according to claim 1, wherein the polyoxazolidine POCis selected from the group consisting of:

wherein R⁶ and R⁷ are, individually, H or a linear or branched alkylgroup with 1 to 10 carbon atoms or an aryl group which is optionallysubstituted.
 7. The composition according to claim 1, wherein thepolyoxazolidine PUC comprises a bis-oxazolidine of formula (IV) or(IV′), and the polyoxazolidine POC comprises a bis-oxazolidine offormula (V):

wherein R², R³, R⁶ and R⁷ are independently from each other H or alinear or branched alkyl group with 1 to 10 carbon atoms.
 8. Thecomposition according to claim 7, wherein R² and R⁶ are H.
 9. Thecomposition according to claim 1, wherein the composition furthercomprises at least one bicyclic oxazolidine BCO.
 10. The compositionaccording to claim 9, wherein the bicyclic oxazolidine BCO has astructure according to formula (VI):

wherein R⁹, R¹⁰, R¹¹ and R¹² are, individually, a linear or branchedalkyl group, or a linear or branched hydroxy alkyl group, or an arylgroup or a cycloalkyl group; R¹³ is H or a linear or branched alkylgroup, or a linear or branched hydroxy alkyl group; R¹⁴, R¹⁵, R¹⁶ andR¹⁷ are, individually, H or a linear or branched alkyl group, or alinear or branched hydroxy alkyl group.
 11. The composition according toclaim 1, wherein the amount of all polyoxazolidines POC and all ofoptionally present bicyclic oxazolidines BCO and the sum of allpolyoxazolidines POU is 80-100% by weight, in regard to the weight ofthe total composition.
 12. The composition according to claim 1, whereinthe weight ratio of the sum of all polyoxazolidines POC to the sum ofall polyoxazolidines POU is 5:95-95:5.
 13. The composition according toclaim 1, wherein the composition further comprises a polyisocyanate thatis a polymer having at least two NCO groups.
 14. The compositionaccording to claim 13, wherein the amount of all polyoxazolidines POCand optionally present bicyclic oxazolidines BCO and the sum of allpolyoxazolidines POU is 5-20% by weight, in regard to the weight of thetotal composition.
 15. A method of using a composition as anon-crystallizing curing agent of a polyisocyanate, the methodcomprising adding a composition to a polyisocyanate, wherein thecomposition comprises: a) at least one polyoxazolidine POU having atleast two urethane groups; and b) at least one polyoxazolidine POChaving at least one carbonato group.
 16. The composition according toclaim 2, wherein in formula (I), R¹ is an ethylene group.
 17. Thecomposition according to claim 2, wherein in formula (I), R⁴ is an-valent residue of a polyisocyanate of a molecular weight of 160-1000g/mol, after removal of n isocyanate groups.
 18. The compositionaccording to claim 1, wherein the polyoxazolidine POU has a structureaccording to formula (Ia):

wherein R¹ is an alkylene group with 2 to 5 carbon atoms; R² and R³ are,individually, H or a linear or branched alkyl group with 1 to 10 carbonatoms or an aryl group which is optionally substituted; and R⁴ is an-valent residue of a polyisocyanate of a molecular weight of 150-4000g/mol, after removal of n isocyanate groups.
 19. The compositionaccording to claim 18, wherein in formula (Ia), R¹ is an ethylene group;and R⁴ is a n-valent residue of a polyisocyanate of a molecular weightof 160-1000 g/mol, after removal of n isocyanate groups.
 20. Thecomposition according to claim 5, wherein in formula (II), R⁵ is anethylene group.
 21. The composition according to claim 5, wherein informula (II), m=2.
 22. The composition according to claim 5, wherein informula (II), R⁸ carries a substituent of the formula (III):


23. The composition according to claim 1, wherein the polyoxazolidinePOC has a structure according to formula (IIa):

wherein R⁵ is an alkylene group with 2 to 5 carbon atoms; R⁶ and R⁷ are,individually, H or a linear or branched alkyl group with 1 to 6 carbonatoms or an aryl group which is optionally substituted.
 24. Thecomposition according to claim 23, wherein in formula (IIa), R⁵ is anethylene group.
 25. The composition according to claim 6, wherein in thepolyoxazolidine POC, at least one of R⁶ and R⁷ is a linear or branchedalkyl group with 1 to 10 carbon atoms or an aryl group, which issubstituted with a methyl, ethyl or isopropyl group.
 26. The compositionaccording to claim 7, wherein in formulas (IV), (IV′) and (V), R², R³,R⁶ and R⁷ are independently from each other a methyl, ethyl or isopropylgroup.
 27. The composition according to claim 7, wherein in formulas(IV), (IV′) and (V), at least one of R², R³, R⁶ and R⁷ is an isopropylgroup.
 28. The composition according to claim 10, wherein in formula(VI), R⁹, R¹⁰, R¹¹ and R¹² are, individually, a linear or branched alkylgroup with 1 to 8 carbon atoms, or a linear or branched hydroxy alkylgroup with 1 to 8 carbon atoms, or an aryl group or a cycloalkyl groupwith 6 to 12 carbon atoms; R¹³ is H or a linear or branched alkyl groupwith 1 to 8 carbon atoms, or a linear or branched hydroxy alkyl groupwith 1 to 8 carbon atoms; R¹⁴, R¹⁵, R¹⁶, and R¹⁷ are, individually, H ora linear or branched alkyl group with 1 to 8 carbon atoms, or a linearor branched hydroxy alkyl group with 1 to 8 carbon atoms.
 29. Thecomposition according to claim 1, wherein the amount of allpolyoxazolidines POC and all of optionally present bicyclic oxazolidinesBCO and the sum of all polyoxazolidines POU is 90-100% by weight, inregard to the weight of the total composition.
 30. The compositionaccording to claim 1, wherein the amount of all polyoxazolidines POC andall of optionally present bicyclic oxazolidines BCO and the sum of allpolyoxazolidines POU is 95-100% by weight, in regard to the weight ofthe total composition.
 31. The composition according to claim 1, whereinthe weight ratio of the sum of all polyoxazolidines POC to the sum ofall polyoxazolidines POU is 10:90-45:55.
 32. The composition accordingto claim 1, wherein the weight ratio of the sum of all polyoxazolidinesPOC to the sum of all polyoxazolidines POU is 25:75-35:65.
 33. Thecomposition according to claim 13, wherein the amount of allpolyoxazolidines POC and optionally present bicyclic oxazolidines BCOand the sum of all polyoxazolidines POU is 5-15% by weight, in regard tothe weight of the total composition.
 34. The composition according toclaim 13, wherein the amount of all polyoxazolidines POC and optionallypresent bicyclic oxazolidines BCO and the sum of all polyoxazolidinesPOU is 6-10% by weight, in regard to the weight of the totalcomposition.